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Biomedical subjects

D W Hunter

Publications and source records attributed to D W Hunter.

At least 127 records · Page 7Linked to original sources
PubMed1987

A new torque guide wire.

A new guide wire that provides markedly improved torque control is described. It was compared with a conventional guide wire in two models, one simulating a drainage tube with numerous side holes and one, the biliary tree. The new wire was much more easily controlled than the conventional guide wire and passed through both models significantly faster (P less than .01 and P less than .005). Although some deterioration in control was noted when it was inserted through a catheter in vivo, the new torque-control wire still exhibited a definite improvement over conventional wires in directional control.

Catheterization, Peripheral↗
PubMed1987

Dialysis access: radiographic evaluation and management.

Complications related to vascular access are the most frequent cause of hospitalization for patients on chronic hemodialysis. Many complications are technical in nature and can be avoided if the original surgery is well planned and carefully performed. Radiologic evaluation plays a critical role in the diagnosis and management of failing access of almost any type.

Angiography↗
PubMed1986

Percutaneous techniques for the management of caliceal diverticula containing calculi.

Most frequently caliceal diverticula are found incidentally on routine excretory urograms. Smaller diverticula are associated with a low incidence of complications but larger diverticula with a narrow communication to the main collecting system will predispose to calculous formation as a result of stasis of urine within the diverticulum. The techniques used and results achieved in 10 patients with such calculi who have been successfully managed percutaneously are discussed. Particular reference is made to techniques used specifically to obliterate the diverticula.

Adult↗
PubMed1986

The double puncture: an effective percutaneous technique for removing complex, multiple renal calculi.

Percutaneous nephrostolithotomy, which can require a double puncture, is presently the method of choice in our institution for the removal of renal stones. Patients that underwent this procedure were evaluated to identify the possible reasons for the double puncture. Of 200 patients evaluated, 14 needed a second tract. The three variables that determined whether a second puncture was needed, in order of importance, were number and size of the stones, with second tracts needed in patients with multiple stones and staghorn calculi; anatomical variations of the renal collecting system itself, with bifid systems the most significant anatomic variation; and the dexterity of the radiologist in performing the puncture and the ability of the urologist to extract the stone. Second tracts were needed more frequently in patients who presented with stones in both the lower and middle poles of the collecting systems.

Humans↗
PubMed1986

Movable core guide wire: evaluation of improved model.

Six commercially available movable core guide wires were compared with each other and with a new design in glass models simulating tortuous vessels. The results demonstrate a wide variability in performance of the commercially available wires and the superiority of the new design.

Angiography↗
PubMed1986

Surface shield: device to reduce personnel radiation exposure.

A simple device is described that can reduce personnel exposure from scatter radiation by up to 75%. The device consists of an oblong piece of shielding (0.75-mm lead equivalent) that is taped to the side of the patient during percutaneous renal stone removal and other interventional procedures. Contrary to other shields and barriers, this does not interfere with access to the patient. Scatter exposure data from phantom studies are presented and the rationale for surface shielding discussed.

Humans↗
PubMed1986

A new retention catheter.

A new retention catheter made of a soft, biocompatible material is described. It has the advantages of the Cope- and Malecot-type systems without their inherent disadvantages. It is easily introduced into virtually any fluid collection and is optimal for smaller collections, such as a normal renal pelvis.

Catheterization↗
PubMed1986

Urine-compatible polymer for long-term ureteral stenting.

Internal double-J ureteral stents were designed from a urine-compatible polymer (C-Flex), and 35 stents were placed in patients. The overall patency rate for the stents was 80%, with most stent failures occurring before 2 months; the follow-up period ranged from 2 to 16 months, with a mean follow-up for all stents of 5.0 months. Stents were considered patent at last follow-up only if they had been in place for at least 2 months. No migration or fracture of the stents occurred. Physical properties of urine-exposed stents were compared with those of virgin tubing and tubing exposed for 1 year to shelf conditions. Stent patency was optimized by increasing urine flow by increasing the patient's voluntary oral intake, administering prophylactic oral antibiotics, and avoiding placement of stents into grossly bloody or infected collecting systems.

Adult↗
PubMed1986

New super-stiff guide wire.

A super-stiff spring guide wire is described, which overcomes some of the drawbacks of the Lunderquist-Ring guide wire. The new wire couples maximum stiffness with a smooth, gradual transition to a floppy tip, thus decreasing the likelihood of breakage and organ perforation.

Radiography↗
PubMed1986

Coil-in-coil technique for vascular embolization.

A new technique for vascular embolization using two Gianturco steel coils is described. The authors used a "coil-in-coil" technique to embolize the arteries of 12 dogs. In this technique a large coil is introduced into the artery followed by a smaller coil, which is delivered with a special introducer into the lumen of the first coil. Two coils can therefore be introduced into a shorter length of vessel. This method was as effective as "packing" the vessel with two coils in a row. The coil-in-coil technique is especially advantageous for use in infants and children with short, anomalous vessels, minimizing the risk of coil dislodgment into normal peripheral vessels.

Animals↗
PubMed1986

Experience with the Amplatz retrievable vena caval filter. Work in progress.

The Amplatz retrievable vena caval filter was designed in an attempt to decrease complications associated with the placement of Mobin-Uddin or Kimray-Greenfield filters. The design allows percutaneous retrieval, thus expanding application of the filter to situations requiring temporary prophylaxis against pulmonary embolism. Filters have been placed in 16 patients, nine (56%) for prophylactic purposes. All filters were easily inserted percutaneously. Complications occurred in three patients; these included complete thrombosis of the inferior vena cava below the filter, misplacement of one filter into the pericaval retroperitoneal tissue, and development of thrombus cranial to the filter. With the current introduction system, the possibility of filter misplacement has been essentially eliminated. No patient experienced symptoms suggestive of pulmonary embolism after filter insertion. One filter retrieval has been performed, with no complications.

Adult↗
PubMed1985

Percutaneous management of ureteral calculi facilitated by retrograde flushing with carbon dioxide or diluted radiopaque dye.

Of 356 patients in whom percutaneous nephrostomy was performed at this institution 59 had ureteral stones. In our experience with the first 36 patients antegrade techniques for ureteral stone extraction had many assets but sometimes they were difficult. Recently, we incorporated a retrograde flushing technique, using carbon dioxide and diluted radiopaque dye, into our percutaneous approach to ureteral stones. Based on our experience with this technique in the next 23 consecutive patients, we believe that percutaneous nephrostolithotomy and retrograde flushing should be added to the armamentarium of urologists committed to the percutaneous endourological approach to ureteral stones.

Carbon Dioxide↗